Joe Rogan podcast guest reveals the most surprising thing about the host after meeting him on the show

Brian Keating has revealed the most surprising thing about Joe Rogan after appearing on his podcast.

The American cosmologist and author of several books, including 'Losing the Nobel Prize', provided an account of his appearance on The Joe Rogan Experience, which lasted over three and a half hours.

The topic of conversation was cosmology, aliens, UFOs and sharing tips about what it's like to be a professor and an actual scientist.

He detailed the most surprising thing about the podcaster, revealing Rogan's Irish goodbye following his outing on the podcast.

In his blog, Keating wrote: "He comes off as a character but can be deadly serious. When it was all over, we posed for a few pictures, and then he left for the bathroom, which was, I realised in hindsight, his form of Irish goodbye! I didn’t see him again."

On Rogan as a host, Keating added: "Joe is an excellent conversationalist, 100% focused, and attention is most important. He comes off as avuncular with folks junior to him, as I still am. He’s the dominant force in podcasting, with each episode eclipsing the previous episode as the world’s most famous episode as soon as it drops."

Joe Rogan during the broadcast of UFC 310. Image: Getty

Keating also debunked a rumour about Rogan's height as he revealed what the UFC commentator is like in person.

"Physically, Joe said he weighs 200lbs, and I estimate he’s about 5’9' tall, contrary to the internet rumours that he’s under 5’6'! I don’t think of him as exceptionally sentimental or emotional," he said. "He works out religiously and has called exercise his favoured form of therapy. To me, he’s a good masculine role model for many young men to emulate."